Integrated Study to Support Skadar Lake of Biosphere Reserve
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UNIVERSITY OF MONTENEGRO FACULTY OF SCIENCES AND MATHEMATICS INTEGRATED STUDY TO SUPPORT THE DESIGNATION OF THE TRANS-BOUNDARY LAKE SKADAR/SHKODRA AS BIOSPHERE RESERVE IN THE FRAME OF THE PROJECT “SUPPORTING THE PROPOSED TRANS-BOUNDARY BIOSPHERE RESERVE OF LAKE SKADAR/SHKODRA AREA THROUGH A PARTICIPATORY APPROACH” PODGORICA, 2011 Integrated study to support the designation of the trans-boundary Lake Skadar/Shkodra as biosphere reserve in the frame of the project “Supporting the proposed Trans-boundary Biosphere Reserve of Lake Skadar/Shkodra area through a participatory approach” DR DANILO MRDAK DR DANKA PETROVIĆ ANA KATNIĆ MARIJAN ERCEG 2 | Page Integrated study to support the designation of the trans-boundary Lake Skadar/Shkodra as biosphere reserve in the frame of the project “Supporting the proposed Trans-boundary Biosphere Reserve of Lake Skadar/Shkodra area through a participatory approach” 1. LOCATION AND AREA CHARACTERISTICS Description of the project area: Lake Skadar and its surrounding: It is situated in Zeta-Skadar valley and it stretches 7 km from the sea, located in south-east part of Montenegro and covers northwestern part of Albania. It is linked with the Adriatic Sea through the River Bojana. It was separated from the Sea by the chain of the high mountains in the distant past. The slopes of the mountain Prokletije spread over northern-east side, while on the southeastern side there are mountains Taraboš and Rumija. The south part covers mountain Sutorman and Sozina and northern- western slopes of Lovćen. Two thirds of the Lake belongs to Montenegro, while one third is on the territory of Albania. Lake’s coasts are indented and rich in numerous bays, peninsulas (islets) and capes, mostly swampy and overgrown with a wide rattan belt. It has very rich and diverse flora. Only the southern part of the coast is rocky with the relicts of the chestnut woods. There are numerous small islands, so called “gorice”. They are low, rocky and overgrown with laurels, ivies, wild pomegranate and shrubbery (CEED 2010). Lake itself: Surface of the Lake size oscillates between 370 km2 of water quantity in summer and 540 km2 in winter season. Surface of the Lake is 475 km2 on average water quantity. Surface of the watershed: 5,490 km2 (80% in Montenegro, 20% in Albania) Length of the coast is 168 kilometers; 110.5 km on the Montenegrin side, 57.5 km in Albania Altitude: 5m above sea level Average depth is 5m; maximum depth is 8.3m Water volumes 1,890. 95x106m3. The Lake features a crypto-depression: some parts of its bottom are lower than the sea level. Those places are called sub-lacustric springs or eyes (”oko“). There are about thirty such places. The deepest measured “eye” is Raduš, 60 m deep. The largest inflow comes from the Moraca River (Montenegro), providing more than 62% of the Lake’s water, while Bojana River (Montenegro and Albania) flows out from the south to the estuary in the Adriatic Sea. 1.1 Lake position and main parameters Skadar Lake is located on the Montenegro-Albanian border, between 42°21’54’’ and 19°09’52’’ in the north (Malo Blato, Sinjac), 42°0315’’ and 19°30’00’’ in the south (Bojana/Buna spring), 42°0315’’ and 19°30’00’’ in the east (near Shkodra), 42°21’19’’ and 19°01’28’’ (near Rijeka Crnojevica). It is the largest of the Balkan Lakes and has a surface area which fluctuates seasonally from approximately 354 to 505,8 km². About 2/3 of Lake is placed in Montengro while 1/3 belong to Albania. The Albanian part of Skadar Lake have less flooded area regarding more steep surrounding terrain (Burić & Radulović, 1983). In terms of water level fluctuation on yearly scale Sakadar Lake water goes from 4,7 to 10m (about six meter in vertical plane). Average depth of Lake is about 5m while maximal length and width is 44 km 3 | Page Integrated study to support the designation of the trans-boundary Lake Skadar/Shkodra as biosphere reserve in the frame of the project “Supporting the proposed Trans-boundary Biosphere Reserve of Lake Skadar/Shkodra area through a participatory approach” and 14 km respectively. During lowest water level condition coastal line is 156 km while including islands it goes up to 207 km. Mountains rise steeply from the Lake's southwestern shores (Taraboš, Rumija, Sutorman, Lovćen), while its northern and north-eastern shores are flat providing an extensive semi-littoral zone. The Lake's south nearshore zone is characterized by a series of islands and bays. Many of the islands along southwestern coast remain disconnected from surrounding lend even during lowest water level while some of them during this event become kind of peninsula. The islands are mainly grouped above Rumija mountain slopes so toward southeast we have following islands: Grmožur, Starčevo, Beška, Moračnik, Gradac, Tophala, Gorica, Gljat, and many smaller ones. In this zone it occurs Lakebays of which bigger ones are: Štitara, Bobovišta, Bljaca, Murići and Raduš. The biggest bay of Skadar Lake is Hotski bay which is almost symmetrically shared among Albania and Montenegro. During high water level Malo blato is also one of the Lake bays while during lover water level it is isolated water body connected with Skadar Lake water mass via river Karatuna. The shore length of Malo balto is about 10 km (Burić & Radulović, 1983). Picture 1. Skadar Lake view toward south 1.2 Hydrology 4 | Page Integrated study to support the designation of the trans-boundary Lake Skadar/Shkodra as biosphere reserve in the frame of the project “Supporting the proposed Trans-boundary Biosphere Reserve of Lake Skadar/Shkodra area through a participatory approach” The Scadar Lake receive it water directly from rainfall on its surface, numerous temporary and constant inflows, springs from coastal zone as well as from strong sublacustral wells known under name “oka” (vrulja). The surface of SkadarLake direct drainage area is 5490 km2 of which 4460 km2 is in Montenegro. Under some specific hydrological conditions Skadar Lake receive water from river Drim (when water level of Drim River is higher than water level of Bojana River and Sakadar Lake) so the drainage are of this river which is 14 000 km2 is indirect and temporary drainage are of Skadar Lake (Radulović, 1983). Most important inflows of Sakadar Lake come from their northern part: Morača River, River Crnojevića, Orahovštica River, Karatuna River, Gostiljska River, Zetica River, Big and Small Mrka River and Plavnica River. Morača River is most important tributary that in total water balance contributes with 62%. Regarding this fact Morača River play most important role during changing of Lakesurface, water mass volume and surface. Most important inflows on Albanian side are: Hotski potok, Proni Tat, Sića, Proni Rjolit and Proni Vraka. Significant amount of Sakdar Lake water comes from sub terrestrial and sub lacustrine wells. Unfortunately data about amount, their consistency, their number and depths are still missing. On northeastern Lakecoast there are three noticed wells (vrulja Funija, Vitoja and Ploče) while in zone of Malo blato and along southern coastal line they are numerous. The most important ones in Malo blato and surrounding area are: Kaluđerovo oko, Krakala, Velja Šuica, Mala Šuica, Bivo, Crno oko, Karuč and Volač. Sub-lacustrine wells of southern part of the Skadar Lake are: Raduš, Krnjice, Šestani, Mrčiluka, Bobovišta, Sijerača and Gradac (Radulović, 1983) .Among them, the best known is Raduš Oko, which has a depth of 60 m at mean-water level. As the Lake is 5 m above sea level, , the oko floor is 55 m below sea level. Water entering the Lake via the okos is substantially harder than river water, probably owing to its direct limestone source (Lasca et al., 1981). Bojana River is the only outflow of Skadar Lake which runs in to the Adriatic Sea and sometimes outflow of Lakewater is stopped with high water level of river Drim that cause floods of this area. During autumn of 2010th and in the end of the winter of this year (2011th) strong and massive floods happened due to extreme precipitation in those periods of year. 1.3 Geology and geomorphology The basin of Skadar Lake is located in the Dinaric mountain system, in one of the tectonic depressions paralleling the mountain range at the foot of the Dinaric Alps and in the foothills of the Prokletija massif. Rumija mountain rise s 1595 m from the southwestern shore of the Lake. While to the north and northeast the Lake bottom gradually slopes upward into the Zeta Plain and the flat area of the Zeta- Skadar depression in Albania. The Lake is surrounded by Paleozoic, Mezozoic and Tertiary rocks. Much of the rock is limestone or dolomite and forms tipical karst topography. Quaternary sediments overlie the 5 | Page Integrated study to support the designation of the trans-boundary Lake Skadar/Shkodra as biosphere reserve in the frame of the project “Supporting the proposed Trans-boundary Biosphere Reserve of Lake Skadar/Shkodra area through a participatory approach” bedrock and consist of various alluvial and colluvial deposits which are generally a few meters thick, and are underlain by Lake and fluvial sediments which range in thickness from 10 to over 350 m (Lasca et al., 1981). The geological and morphological structure of Skadar Lake drainage area is highly complex built of several zones. Lake Skadr's basin and the major part of its drainage are located in the High-Karst Zone. The rock of High-Karst are composed of (1) minor amounts of Upper-Paleozoic limestone and conglomerate and (2) major outcrops of Mezozoic rock in which carbonate rocks dominate. There are also clastic and flysch deposits of the Lower and Middle Triassic and Middle Jurassic in which Triassic, Jurassic and Cretaceous limestone occurs.